Little is known about Johnson, and no other picture by him has been identified. He was listed as a "Photographic Artist" in the directory of the industrial city of Blackburn, Lancashire, during the mid-1850s, suggesting that he ran a professional studio. Whether or not this photograph was made for a commercial purpose, it is clearly an application of the still-new medium to a traditional subject of art, and Johnson showed it as such at the 1856 exhibition of the Photographic Society of London.

The intricate web of masts and rigging of the listing "Jane Tudor," an American vessel in the port of Conway, perhaps waiting to be loaded with Welsh slate, recalls picturesque aspects of painted harbor scenes. But in a departure from painterly precedents, Johnson focused his entire composition on a single surprising element—the ship's anchor, shown in perfect frontal silhouette, black against white, hanging in midair like a plumb. Although the anchor helps orient the viewer spatially by providing the only true vertical in the photograph, it also, paradoxically, destabilizes the composition, as it seems to pull the ship over with the sheer force of its graphic design.